To describe a shortened name or phrase, but not of a personal nature, that takes less time to speak or write. McDonald's restuarant becomes McD's, or Micky D's, or Trader Joes becomes TJ's. FYI, BYOB, FOB (Friends of Bill) are further illustrations. Personal names would not fall under this definition, so that William becoming Bill would still remain a nickname.

Do you have a quickname for WalMart? Wally's
What would be a good quickname for the Internal Revenue Service? The IRS